Do teeth whitening kits really work?
Many high-street shops sell teeth whitening products, like strips, gels and toothpastes, which claim to make teeth whiter. But how effective are they? And are teeth whitening kits safe? Here, I look at how well different teeth whitening products work.
Do teeth whitening kits actually work?
There are lots of over-the-counter teeth whitening products available, such as:
- toothpastes
- whitening strips
- paint-on kits
- laser or LED whitening kits
In the UK, teeth whitening kits that you use at home aren’t allowed to contain more than 0.1 per cent hydrogen peroxide. Hydrogen peroxide is the chemical that bleaches your teeth to make them look whiter.
This level of hydrogen peroxide is lower than what’s needed to effectively whiten teeth. So, although at-home whitening kits may whiten your teeth a little, the results don‘t usually last for long. Your dentist can prescribe stronger whitening products that provide longer-lasting results.
Are at-home teeth whitening kits safe?
In the UK, teeth whitening kits sold in high-street shops are generally considered safe, as they must meet strict regulations.
However, some products have been found to use alternative ingredients such as sodium chlorite. The effects of these chemicals on tooth enamel (the hard protective coating on your teeth) are unclear at the moment. But it’s thought that they could damage your teeth.
How are whitening kits in shops different to whitening at the dentist?
A dentist can legally prescribe or perform whitening treatment which contains up to 6 per cent hydrogen peroxide. This is 600 times more concentrated than what’s found in over-the-counter kits. Because it’s so much stronger, professional teeth whitening gel goes deeper into your tooth structure. This leads to much whiter teeth and a longer-lasting result.
Are teeth whitening products sold on the internet safe?
It’s important to avoid cheap products with unrealistic claims of whitening results. There is a chance that products bought over the internet could be counterfeit or contain harmful chemicals.
Some kits have been seized for containing dangerously high levels of hydrogen peroxide.
If a whitening kit that hasn’t been prescribed by your dentist contains more than 0.1 per cent hydrogen peroxide, it could be an illegal product. Always check the percentage before you buy. High levels of hydrogen peroxide may cause:
- burns to your gums
- receding gums
- damage to nerves and enamel
- extreme sensitivity
Do whitening toothpastes work?
Whitening toothpastes containing abrasives (things that grind or polish) can whiten teeth a little. This is because the abrasives remove surface stains. And they may be useful to remove surface staining after professional whitening.
However, the abrasives in these toothpastes can also remove enamel in addition to surface staining. Thinning of the enamel can cause dentine to show (the tissue which sits below the top hard surface of your teeth). Dentine is more yellow than enamel. Because of this, overuse of whitening toothpastes that contain abrasives could remove enamel over time. This could make your teeth appear more yellow.
How long does professional teeth whitening last?
Teeth whitening doesn’t last forever. Your teeth will become darker over time due to:
- loss of the bleaching effect
- natural yellowing of teeth
- staining from food and drinks like coffee and red wine
If you smoke, this will also discolour your teeth.
Visiting the hygienist and using a short top-up course of whitening gel can help to keep your teeth white. This can be prescribed by your dentist. A top-up is usually required within 18 to 24 months of having a whitening treatment done.
If you want to find out more about professional teeth whitening, visit your dentist.
-
Sources Sources
- Teeth whitening. British Dental Association. BDA. Bda.org, last accessed 10 April 2026
- Safe smiles: Tooth whitening and the law. Safe Smiles. Dentalhealth.org, last accessed May 2026
- Greenwall-Cohen J, Francois P, Silikas N, et al. The safety and efficacy of 'over the counter' bleaching products in the UK. Br Dent J. 2019 Feb;226(4):271-276. doi: 10.1038/s41415-019-0011-6
- The safest way to get a whiter smile. Safe Smiles. Dentalhealth.org, last accessed May 2026
- Dentists and Which? warn of risks from buying teeth whitening products online. BDA. Bda.org, published May 2021
- BDJ. BDJ study on dangers of teeth whitening products prompts large response. Br Dent J 2019; 226: 391. https://doi.org/10.1038/s41415-019-0188-8
- About tooth whitening. Safe Smiles. Dentalhealth.org, last accessed May 2026
- Epple M, Meyer F, Enax J. A Critical Review of Modern Concepts for Teeth Whitening. Dent J (Basel). 2019 Aug 1;7(3):79. doi: 10.3390/dj7030079
- Kansal S, Jindal L, Garg K, et al. (2020). Discoloration of Teeth: A Literature Review. International Journal of Health and Clinical Research, 3(2), 58–62
- Personal communication, [Neil Sikka, Director of Dentistry, Bupa UK], May 2026.
About our health information
At Bupa we produce a wealth of free health information for you and your family. This is because we believe that trustworthy information is essential in helping you make better decisions about your health and wellbeing.
Our information has been awarded the PIF TICK for trustworthy health information. It also follows the principles of the The Information Standard.
More general health advice articles
Did you find our advice helpful?
We’d love to hear what you think. Our short survey takes just a few minutes to complete and helps us to keep improving our healthy lifestyle articles.
Legal disclaimer
This information was published by Bupa's Health Content Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals and deemed accurate on the date of review. Photos are only for illustrative purposes and do not reflect every presentation of a condition.
Any information about a treatment or procedure is generic, and does not necessarily describe that treatment or procedure as delivered by Bupa or its associated providers.
The information contained on this page and in any third party websites referred to on this page is not intended nor implied to be a substitute for professional medical advice nor is it intended to be for medical diagnosis or treatment. Third party websites are not owned or controlled by Bupa and any individual may be able to access and post messages on them. Bupa is not responsible for the content or availability of these third party websites. We do not accept advertising on this page.
